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|
use std::{io, time::SystemTime};
use log::{debug, info, trace, warn};
fn setup_logging(verbosity: u64) -> Result<(), fern::InitError> {
let mut base_config = fern::Dispatch::new();
base_config = match verbosity {
0 => {
// Let's say we depend on something which whose "info" level messages are too
// verbose to include in end-user output. If we don't need them,
// let's not include them.
base_config
.level(log::LevelFilter::Info)
.level_for("overly-verbose-target", log::LevelFilter::Warn)
}
1 => base_config
.level(log::LevelFilter::Debug)
.level_for("overly-verbose-target", log::LevelFilter::Info),
2 => base_config.level(log::LevelFilter::Debug),
_3_or_more => base_config.level(log::LevelFilter::Trace),
};
// Separate file config so we can include year, month and day in file logs
let file_config = fern::Dispatch::new()
.format(|out, message, record| {
out.finish(format_args!(
"[{} {} {}] {}",
humantime::format_rfc3339_seconds(SystemTime::now()),
record.level(),
record.target(),
message
))
})
.chain(fern::log_file("program.log")?);
let stdout_config = fern::Dispatch::new()
.format(|out, message, record| {
// special format for debug messages coming from our own crate.
if record.level() > log::LevelFilter::Info && record.target() == "cmd_program" {
out.finish(format_args!(
"DEBUG @ {}: {}",
humantime::format_rfc3339_seconds(SystemTime::now()),
message
))
} else {
out.finish(format_args!(
"[{} {} {}] {}",
humantime::format_rfc3339_seconds(SystemTime::now()),
record.level(),
record.target(),
message
))
}
})
.chain(io::stdout());
base_config
.chain(file_config)
.chain(stdout_config)
.apply()?;
Ok(())
}
fn main() {
let cmd_arguments = clap::App::new("cmd-program")
.arg(
clap::Arg::with_name("verbose")
.short("v")
.long("verbose")
.multiple(true)
.help("Increases logging verbosity each use for up to 3 times"),
)
.get_matches();
let verbosity: u64 = cmd_arguments.occurrences_of("verbose");
setup_logging(verbosity).expect("failed to initialize logging.");
info!("MyProgram v0.0.1 starting up!");
debug!("DEBUG output enabled.");
trace!("TRACE output enabled.");
// Emulate a library we're using which has tons of debugging on the 'info'
// level.
info!(target: "overly-verbose-target", "hey, another library here, we're starting.");
for i in 0..5 {
info!("executing section: {}", i);
debug!("section {} 1/4 complete.", i);
info!(target: "overly-verbose-target", "completed operation.");
debug!("section {} 1/2 complete.", i);
info!(target: "overly-verbose-target", "completed operation.");
info!(target: "overly-verbose-target", "completed operation.");
debug!("section {} 3/4 complete.", i);
info!("section {} completed!", i);
}
warn!(target: "overly-verbose-target", "AHHH something's on fire.");
info!("MyProgram operation completed, shutting down.");
}
|
